Digressing slightly, but promising to connect, I just love the people who prattle about how having a flat tax would make everything so simple. Whether you have 1 bracket or 100 has zero effect on return prep complexity. (More brackets = more complexity for the people who have to come up with the Tax Tables, but not the taxpayer preparing the return.) The complexity, and the bulk of the Code, involves defining income.

Most flat tax proposals are simple based on the fact that they'd remove the various deductions and different investment income rates, etc. But you're completely right, there's no reason you couldn't do that with graduated income tax brackets too. But you're completely right -a flat tax isn't simple by virtue of being flat.